35.1 A Horse with Stripes

One of the author’s partners is fond of saying, “Sometimes it’s not a zebra, sometimes it’s just a horse with stripes.” While anaphylaxis is something every allergy practice must be prepared to treat, fortunately it’s fairly uncommon. There are other adverse events that can happen with higher frequency that the clinician also needs to be prepared to recognize and treat. Some of these reactions are similar to or can mimic anaphylaxis. Some of them can be part of an anaphylactic reaction. Establishing protocols and educating not only yourself, but your allergy and office staff, on early recognition and the steps to take to manage/treat these other reactions will help your office be prepared to handle whatever manner of equine should present itself that day.

35.2 Local Reactions

Local reactions come in two types: Immediate or delayed.

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  Immediate: Occur within an hour of subcutaneous immunotherapy (SCIT) injection; frequently seen.

  
  
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  Delayed: Occur 8 to 24 hours after SCIT injection or skin testing; frequently seen.

Symptoms include swelling of variable size, redness, itching at the site of the injection/testing area.

Both types can be treated with oral antihistamines, ice, and topical corticosteroid ointments. Premedication with an oral antihistamine prior to injection can help.

Large local reactions result in more than 30 mm in diameter (larger than half-dollar coin) and patients should be instructed to report their occurrence. Although repeated large local reactions show no tendency to progress to systemic reactions, some providers will adjust the dose of SCIT for these large reactions.